Conventionally, a supercharger type engine includes a supercharger system to supercharge intake air drawn into the engine.
In a supercharger type engine, a turbocharger compresses intake air, and consequently, the compressed intake air increases in temperature. As it is, a charging efficiency of the compressed intake air may decrease, and the compressed intake air may cause knocking when the engine is, for example, at high load. In consideration of this, compressed intake air may be generally cooled. Various configurations may be proposed to cool compressed intake air. For example, an intercooler may be equipped between a turbocharger and multiple intake ports to cool intake air, which is compressed in the turbocharger and is at high temperature. Thereafter, the intake air cooled with the intercooler may be distributed into multiple intake ports.
Various air intake apparatuses may be proposed to comply with a regulation related to exhaust gas and/or to reduce fuel consumption. For example, an EGR system may be employed to draw a part of exhaust gas as EGR gas into either or both of an inlet of a turbocharger at a low-pressure side and an outlet of the turbocharger at a high-pressure side. In this case, an EGR cooler may be equipped to an EGR-gas inlet passage to cool EGR gas.